Using a fork, stir yogurt mixture into flour mixture until large dough clumps form. Use your hands to press the dough against the bowl into a ball. (The dough will be sticky in places, and there may not seem to be enough liquid at first, but as you press, the dough will come together).

Place on a lightly floured surface and pat into a 7- to 8-inch circle about 3/4-inch thick. Sprinkle with remaining 1 tsp. of sugar. Use a sharp knife to cut into 8 triangles; place on a cookie sheet (preferably lined with parchment paper), about 1 inch apart. Bake until golden, about 15 to 17 minutes. Cool for 5 minutes and serve warm or at room temperature.